Abstract
BackgroundChildren with cerebral palsy (CP) often show impaired selective motor control (SMC) that induces limitations in motor function. Children with CP can improve aspects of pathological gait in an immediate response to visual biofeedback. It is not known, however, how these gait adaptations are achieved at the neural level, nor do we know the extent of SMC plasticity in CP.AimInvestigate the underlying SMC and changes that may occur when gait is adapted with biofeedback.MethodsTwenty-three ambulatory children with CP and related (hereditary) forms of spastic paresis (Aged: 10.4 ± 3.1, 6–16 years, M: 16/F: 9) were challenged with real-time biofeedback to improve step length, knee extension, and ankle power while walking on an instrumented treadmill in a virtual reality environment. The electromyograms of eight superficial muscles of the leg were analyzed and synergies were further decomposed using non-negative matrix factorization (NNMF) using 1 to 5 synergies, to quantify SMC. Total variance accounted for (tVAF) was used as a measure of synergy complexity. An imposed four synergy solution was investigated further to compare similarity in weightings and timing patterns of matched paired synergies between baseline and biofeedback trials.ResultsDespite changes in walking pattern, changes in synergies were limited. The number of synergies required to explain at least 90% of muscle activation increased significantly, however, the change in measures of tVAF1 from baseline (0.75 ± 0.08) were less than ±2% between trials. In addition, within-subject similarity of synergies to baseline walking was high (>0.8) across all biofeedback trials.ConclusionThese results suggest that while gait may be adapted in an immediate response, SMC as quantified by synergy analysis is perhaps more rigidly impaired in CP. Subtle changes in synergies were identified; however, it is questionable if these are clinically meaningful at the level of an individual. Adaptations may be limited in the short term, and further investigation is essential to establish if long term training using biofeedback leads to adapted SMC.
Highlights
Walking requires refined coordination of muscle activation
These results suggest that while gait may be adapted in an immediate response to biofeedback, it is questionable if this involves an adaptation of selective motor control (SMC)
We showed that ambulatory children with cerebral palsy (CP) show a higher total variance accounted for (tVAF) at each synergy level when compared to typically developing (TD) children (Steele et al, 2015; Cappellini et al, 2016, 2018; Goudriaan et al, 2018)
Summary
Walking requires refined coordination of muscle activation. The current theory in motor control suggests the central nervous system acts to simplify this complexity by the recruitment of a small number of muscle synergies (Tresch et al, 2002). A muscle synergy, or module, is the balanced temporal activation of a group of muscles to create a specific movement These patterns have been described as primitives due to their nature as building blocks for movement and because they are linked to ancestral generation of locomotion, observed across a number of animal species (Dominici et al, 2011). Understanding these fundamental motor control strategies may help to develop effective treatments for individuals with impaired motor function. How these gait adaptations are achieved at the neural level, nor do we know the extent of SMC plasticity in CP
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
